Patent GB-845164-A (GB)
Title: Speed control device
IPC: F02D9/00
Filed: 1958-08-13
Abstract: 845,164. Controlling motor vehicles. PERFECT CIRCLE CORPORATION. Aug. 13, 1958 [Sept. 30, 1957], No. 25986/58. Class 79(5). A speed control device which is operable from the throttle control member provides resistance to the actuation thereof beyond a predetermined speed and may also be set to operate the throttle control member to maintain a predetermined speed. The device may be rendered inoperative in response to movement of the brake pedal. The throttle is operated by a pedal 26, Fig. 1, via links 30 and 31 and other members, not shown, and the device is connected to the pedal 26 by a link 47. A preloaded spring 50 is provided which opposes continued movement of the pedal 26 beyond the point at which the device operates. The link 47 is connected to an arm 44 Fig. 5, rotatably mounted on a fixed shaft 36 and carrying a stop member 41. Also mounted upon the shaft 36 is a member 51 having a downwardly depending portion 62 carrying a nut 57 which operates upon a threaded extension of the shaft of an electric motor 55. A centrifugal governor 66 is connected to the engine through a flexible cable 76 and to the speedometer through pinions 77, 80 and a flexible cable 83. The governor is provided with an arm 95 which may be raised against the pressure of a spring 96 by the extensions 91 of the weights and is pivotally connected to a member 106 which is rotatably mounted on a screw 105 and yieldably connected to a member 104 also rotatably mounted upon the screw 105. An insulating block 131 attached to the member 51 carries a contact member 126 and an extension of the stop member 41 carries a contact member 100. The member 104 has contacts 125 and 103 which may be brought into engagement with the contacts 126 and 100 respectively. As the pedal 26 is depressed, the stop member 41 is rotated in a clockwise direction and as the speed of the motor increases, the governor operates to rotate the member 104 and close the contacts 103, 100 ' causing the motor 55 to rotate and move the nut 57, thus rotating the member 51 until, at a predetermined position it abuts the member 41 and rotates. it in a counter-clockwise direction, opening the contacts 100, 103, stopping the motor 55. If the pedal 26 is allowed to move towards the idle position, or if road conditions cause a decrease in the engine speed, the governor rotates the arm 104 to close the contacts 125, 126 and the motor 55 rotates in the opposite direction swinging the member 51 out of engagement with the member 41. If the pedal 26 moves to the idle position, the nut 57 moves to the end of the screw 56. If the vehicle speed decreases to some extent and then remains steady, the nut 57 will move to the left until the contacts 125 and 126 are separated and the motor stops. The nut is of a construction which prevents jamming at the ends, being provided with balls in circumferential grooves which co-operate with arcuate helical grooves of the screw. The device may be set to operate the throttle with. the driver's foot removed from the pedal 26 by locking the members 41 and 51 together by a spring loaded catch member 141 held in the locked position by an electromagnet 140. If the vehicle speed falls below the predetermined speed, the arm 104 will move anticlockwise. (Fig. 7) and the contacts 125, 126 will be closed operating the motor 55 and thus the members 51 and 41 and, through the rod 47, the pedal 26 to increase the vehicle speed. If the vehicle speed exceeds the predetermined speed the contacts 100, 103 will be closed to operate the motor in the opposite direction and so decrease the vehicle speed. A switch 167 forming part of the electromagnet circuit, is incorporated on the brake pedal, a slight movement of which restores the vehicle to normal control. The speed at which the device operates may be predetermined by varying the load upon the governor spring 96, for which purpose the upper end of the spring bears against a member 171, Fig. 6, which may be raised or lowered by the pull exerted on a cable 175 enclosed within a sheath 177 and terminating in a manually operated rack and pinion mechanism 181 attached to the steering column. Incorporated within the rack and pinion mechanism is a push button switch operating the electromagnet 141. The electric circuits are shown in Fig. 4.